The spread in our results for the GEF estimate illustrates the range of possible outcomes that one may expect for different models that do lead to the same values of \(\xi \)  and \(H\)  at the end of inflation, but which differ in the way in which they reach the end of inflation, specifically, in the way in which the conductivity \(\sigma \)  evolves prior to the end of inflation.
In addition to this model-related uncertainty, the GEF estimate features a systematic uncertainty stemming from the fact that it is not capable of accounting for the time dependence of the parameters \(\xi \) , \(H\) , \(\Delta \) .
(In a full, time-resolved GEF run for a specific model, this is of course not a problem.)
This uncertainty is comparable to the spread in our results for different values of \(\Delta \) .
To first approximation, one may therefore also completely neglect the \(\Delta \)  dependence of the GEF estimate and simply work with a fixed \(\Delta \)  value.
This is precisely what we will do in the remainder of this paper, in which we will focus on the GEF estimate for \(\Delta = 1\) .
As shown in Ref. [1]}, this estimate is still capable of approximating the outcome of specific models at a level that is comparable to the full \(\Delta \) -dependent GEF estimate.
